The present invention relates generally to friction materials and, more particularly, to methods of making friction materials having metal fibers dispersed therein.
Friction materials of the type that are used in brake pads and clutch plates ordinarily contain one or more fiber materials, filler materials, and a resin binder. In order to improve their performance, various special components may be added to the friction materials. The addition of metal fibers and/or particles have been found to improve fade and heat resistance while providing good endurance and increased strength. However, when it has been attempted to use papermaking machines to manufacture friction materials having metal fibers incorporated therein, it has been found that the fibers and/or particles tend to settle toward the bottom of the material during the manufacturing process. Yet, it is highly desirable to use papermaking techniques to manufacture friction materials since it is a rapid and efficient method of manufacture which allows hydrated cellulose fibers of increased strength to be used in the formulation in place of asbestos.
Accordingly, it is a principal object of the invention to provide an efficient method of manufacturing improved friction materials.
It is another object of the present invention to provide an improved method of manufacturing friction materials which contain cellulose fibers and metal fibers.
It is a further object of the present invention to provide a method of manufacturing friction materials incorporating cellulose and metal fibers on a papermaking machine whereby the final product has the metal fibers substantially evenly dispersed therethrough.